Rite of the Winterwolf
The Rite of the Winterwolf is essentially a rite of ending. When a Garou is so old that he is not able to help anymore, damaged beyond repair, or simply not strong enough to be of help, they become a burden on the sept. And as the tenth rule of the Litany states: Do not suffer thy people to tend thy sickness.
These garou perform then a ritual to become a Winterwolf. They say their farewells and hear their friends tell stories of them. And as the sept drinks and remembers the Garou's greatest deeds, he slowly retreats to a place where he can find his rest, and takes his own life with a silver knife.
Though not many Garou live to a point where they can actually perform this rite (most die on a battlefield before ever reaching any of the former mentioned states), it is a very common rite, and a high honour to perform it.